Aromatic carboxylic acids

ABSTRACT

An aromatic carboxylic acid compound of the following formula: &lt;IMAGE&gt;  wherein R1 is a C1-C6 alkyl group, each of X1 and X2 is independently a C1-C4 alkyl group, m is an integer of 0 or 1, and n is an integer of 0, 1 or 2, or a salt thereof.

This is a division of application Ser. No. 08/367,183 filed Dec. 27,1994 now U.S. Pat. No. 5,506,194, which is a 371 of application ofPCT/JP93/00867 filed Jun. 25, 1993.

TECHNICAL FIELD

The present invention relates to pyrazole derivatives, a herbicidecontaining the pyrazole derivative(s) as an active ingredient, and novelintermediate compounds useful for the production of the pyrazolederivatives.

TECHNICAL BACKGROUND

During a growing period of corn, etc., a triazine-based herbicide suchas atrazine and acid anilide-based herbicides such as alachlor andmetolachlor have been conventionally used. However, atrazine shows lowefficacy to gramineous weeds, and alachlor and metolachlor show lowefficacy to broad-leaved weeds. It is therefore difficult at present tocontrol gramineous weeds and broad-leaved weeds together with a singleherbicide. Further, the above herbicides are undesirable in view of anenvironmental problem due to their high dosage requirement.

On the other hand, it is known that specific 4-benzoyl-pyrazolederivatives have herbicidal activity (see JP-A-63-122672,JP-A-63-122673, JP-A-63-170365, JP-A-1-52759, JP-A-2-173 andJP-A-2-288866).

Further, for example, pyrazolate of the following formula is known as acommercial herbicide. ##STR2##

However, pyrazole derivatives having a thiochroman ring such ascompounds of the present invention to be specified later are not knownyet, and derivatives having an alkoxyimino group are not known, either.

Meanwhile, the commercially available pyrazolate is a herbicide for usein a paddy field, and it hardly has herbicidal activity when used in aplowed field. Further, in foliar treatment, the 4-benzoyl-pyrazolederivatives that have been already disclosed have activity tobroad-leaved weeds such as cocklebur, velvetleaf, slender amaranth,etc., in a plowed field, while their activity is practicallyinsufficient. Further, they show very poor activity to grasses such asgreen foxtail, fingergrass, barnyardgrass, etc. In soil treatment, theabove derivatives show very poor activity to grasses such as greenfoxtail, crabgrass, barnyardgrass, etc. and to broad-leaved weeds suchas cocklebur, velvetleaf, slender amaranth, etc.

DISCLOSURE OF THE INVENTION

It is a first object of the present invention to provide a novelpyrazole derivative which shows high selectivity to corn, wheat andbarley and which can control grasses and broad-leaved weeds at lowdosage by any one of foliar treatment and soil treatment.

It is a second object of the present invention to provide a herbicidecontaining the above pyrazole derivative as an active ingredient.

It is a third object of the present invention to provide a novelintermediate compound useful for the production of the above novelpyrazole derivative.

The above first object is achieved by a pyrazole derivative of theformula. ##STR3##

(wherein R¹ is a C₁ -C₆ alkyl group, each of R², X¹ and X² isindependently a C₁ -C₄ alkyl group, R³ is hydrogen or a C₁ -C₄ alkylgroup, m is an integer of 0 or 1, and n is an integer of 0, 1 or 2.) ora salt thereof.

The above second object is achieved by a herbicide containing thepyrazole derivative of the above formula (I) and/or a salt thereof asactive ingredient.

Further, the above third object is achieved by an aromatic carboxylicacid derivative of the formula, ##STR4##

(wherein R¹ is a C₁ -C₆ alkyl group, each of X¹ and X² is independentlya C₁ -C₄ alkyl group, m is an integer of 0 or 1, and n is an integer of0, 1 or 2), or a salt thereof.

PREFERRED EMBODIMENTS FOR WORKING THE INVENTION

First, the novel pyrazole derivative of the present invention will beexplained.

The novel pyrazole derivative of the present invention includescompounds of the formula (I). ##STR5##

In the formula (I) R¹ is a C₁ -C₆ alkyl group such as methyl, ethyl,propyl, butyl, pentyl or hexyl, and each of R², X¹ and X² isindependently a C₁ -C₄ alkyl group such as methyl, ethyl, propyl such asn-propyl or i-propyl or butyl such as n-butyl. The propyl, butyl, pentyland hexyl may be linear or branched as described above. R¹ is preferablya C₁ -C₄ alkyl group, more preferably methyl, ethyl or i-propyl.

Each of R², X¹ and X² is independently a C₁ -C₄ alkyl group, and the C₁-C₄ alkyl includes methyl, ethyl, propyl such as n-propyl or i-propyland butyl such as n-butyl. The propyl and butyl may be linear orbranched as described above. Preferred is methyl or ethyl.

R³ is hydrogen or a C₁ -C₄ alkyl group, and the C₁ -C₄ alkyl groupincludes those specified regarding the above R², X¹ and X² Preferred ishydrogen or methyl and more preferred is hydrogen. The propyl and butylmay be linear or branched.

m represents the number of X² and m is an integer of 0 or 1. When m is1, the site where X² is substituted is preferably the 8-position.

n represents the number of oxygen atom(s), and n is an integer of 0, 1or 2. That is, when n is 0, sulfide is represented, when n is 1,sulfoxide is represented, and when n is 2, sulfone is represented.Preferred is n=2, i.e., sulfone.

The pyrazole derivative of the formula (I) can have the following threestructures due to its tautomerism. The pyrazole derivative of thepresent invention may be a compound having any one of these structuresor may be a mixture of compounds having these structures. ##STR6##

Further, the pyrazole derivative of the formula (I) includes geometricalisomers with regard to an alkoxyimino group as follows. The pyrazolederivative of the present invention may be any one of the followingisomers, or may be a mixture of the isomers. When m is 1, thesubstituent X² can bond to the 7-position or the 8-position, while X²preferably bonds to the 8-position. ##STR7##

Further, the pyrazole derivative of the formula (I) is an acidicsubstance, and can be easily converted to a salt by treatment with abase. The salt is also included in the pyrazole derivative of thepresent invention.

The above base is selected from known bases without any limitation, andexamples thereof include organic bases such as amines and anilines andinorganic bases such as sodium compounds and potassium compounds. Theamines include monoalkylamine, dialkylamine and trialkylamine. The alkylgroup in the alkylamines is generally a C₁ -C₄ alkyl group. The anilinesinclude aniline, monoalkylaniline and dialkylaniline. The alkyl group inthe alkylanilines is generally a C₁ -C₄ alkyl group. The sodiumcompounds include sodium hydroxide and sodium carbonate. The potassiumcompounds include potassium hydroxide and potassium carbonate.

The herbicide of the present invention contains the novel pyrazolederivative of the formula (I) and/or a salt thereof as activeingredient. These compounds may be used as follows. The pyrazolederivative and/or the salt thereof are/is mixed with a liquid carriersuch as a solvent or a solid carrier such as a fine mineral powder, andthe mixture is prepared into the form of a wettable powder, an emulsion,a dust or granules. For imparting these compounds with emulsifiability,dispersibility and wettability in producing the above preparations, asurfactant can be added.

When the herbicide of the present invention is used in the form of awettable powder, a composition is prepared by mixing 10 to 55% by weightof the pyrazole derivative of the present invention or the salt thereof,40 to 88% by weight of a solid carrier and 2 to 5% by weight of asurfactant, and the resultant composition may be used. When it is usedin th form of an emulsion, the emulsiton can be prepared by mixing 20 to50% by weight of the pyrazole derivative of the present invention or thesalt thereof 35 to 75% by wight of a solvent and 5 to 15% by weight of asurfactant.

On the other hand, when the herbicide of the present invention is usedin the form of dust, the dust can be prepared by mixing 1 to 15% byweight of the pyrazole derivative of the present invention or the saltthereof, 80 to 97% by weight of a solid carrier and 2 to 5% by weight ofa surfactant. Further, when it is used in the form of granules, thegranules can be prepared by mixing 1 to 15% by weight of the pyrazolederivative of the present invention and/or the salt thereof. 80 to 97%by weight of a solid carrier and 2 to 5% by weight of a surfactant. Thissolid carrier is selected from fine mineral powders, and examples ofthese fine mineral powders include diatomaceous earth, oxides such asslaked lime, phosphates such as apatite, sulfates such as gypsum, andsilicates such as talc, pyrophyllite, clay, kaolin, bentonite, acidclay, white carbon, powdered quartz and a silica powder.

The above solvent is selected from organic solvents, and specificexamples of the organic solvents include aromatic hydrocarbons such asbenzene, toluene and xylene, chlorinated hydrocarbons such aso-chlorotoluene, trichloroethane and trichloroethylene, alcohols such ascyclohexanol, amyl alcohol and ethylene glycol, ketones such asisophorone, cyclohexanone and cyclohexenyl-cyclohexanone, ethers such asbutyl cellosolve, diethyl ether and methyl ethyl ether, esters such asisopropyl acetate, benzyl acetate and methyl fumarate, amides such asdimethylformamide, and mixtures of these.

Further, the above surfactant is selected from anionic surfactants,nonionic surfactants, cationic surfactants and amphoteric surfactants(amino acid and betaine).

The herbicide of the present invention may contain other herbicidallyactive component as required in combination with the pyrazole derivativeof the formula (I) and/or the salt thereof as an active ingredient. This"other" herbicidally active component includes known herbicides such asphenoxy, diphenylether, triazine, urea, carbamate, thiolcarbamate, acidanilide, pyrazole, phosphoric acid, sulfonylurea and oxadiazonherbicides. This "other" herbicide is properly selected from theseherbicides.

Further, the herbicide of the present invention may be used incombination with an insecticide, a fungicide, a plant growth regulatorand a fertilizer as required.

The novel pyrazole derivative of the present invention can be producedby the following method (A) or (B). ##STR8##

The compound of the formula (II) and the compound of the formula (III)are allowed to react in an inert solvent in the presence of adehydrating agent such as N,N'-dicyclohexylcarbodiimide (to beabbreviated as DCC hereinafter) and a base to produce the pyrazolederivative of the formula (I).

In the above method (A), the compound of the formula (III) is preferablyused in an amount of 1.0 to 3.0 per mole of the compound of the formula(II). The molar amount of DCC is preferably 1.0 to 1.5 times as large asthe molar amount of the compound of the formula (II). The base usedtogether with DCC is not specially limited, while potassium carbonate,sodium carbonate, or the like is preferably used in an amount of 0.5 to2.0 mol per mole of the above compound of the formula (II). The inertsolvent is not specially limited if it is inert to the reaction, whilet-butyl alcohol, t-amyl alcohol and i-propyl alcohol are preferred. Thereaction temperature can be set in the range of from room temperature tothe boiling point of the solvent, while it is preferably 50° to 100° C.

The pyrazole compound of the formula (III) used as a reaction reagent inthe above method (A) can be synthesized, for example, by the methoddescribed in JP-A-61-257974.

The aromatic carboxylic acid derivative of the formula ##STR9##

(wherein R¹ is a C₁ -C₆ alkyl group, each of X¹ and X² is independentlya C₁ -C₄ alkyl group, m is an integer of 0 or 1, and n is an integer of0, 1 or 2), which is used for the reaction with the compound of theformula (III), is a novel compound described in no literature and usefulas an intermediate compound for the production of the pyrazolederivative of the present invention.

The aromatic carboxylic acid derivative of the formula (II) includesgeometrical isomers with regard to an alkoxyimino group as follows. Thearomatic carboxylic acid derivative of the present invention may be anyone of the following isomers or may be a mixture of these isomers. Whenm is 1, the substituent X² can bond to any one of the 7-position and8-position, while it preferably bonds to the 8-position. ##STR10##

Further, the aromatic carboxylic acid derivative of the formula (II) isan acidic substance, and can be easily converted to a salt by treatingit with a base. This salt is also included in the aromatic carboxylicacid derivative of the present invention.

The above base is selected from known bases without any limitation, andexamples thereof include organic bases such as amines and anilines andinorganic bases such as sodium compounds and potassium compounds. Theamines include monoalkylamine, dialkylamine and trialkylamine. The alkylgroup in the alkylamines is generally a C₁ -C₄ alkyl group. The anilinesinclude aniline, monoalkylaniline and dialkylaniline. The alkyl group inthe alkylanilines is generally a C₁ -C₄ alkyl group. The sodiumcompounds include sodium hydroxide and sodium carbonate. The potassiumcompounds include potassium hydroxide and potassium carbonate.

As described above, the aromatic carboxylic acid derivative of theformula (II) includes sulfide (n=0), sulfoxide (n=1) and sulfone (n=2).These compounds are produced by the following means (x) and (y).##STR11##

In the above formulas (IV) and (VI), Hal shows halogen such as chlorine,bromine and so on.

The thiochroman-4-one of the formula (IV) used as a starting materialcan be produced by a variety of methods such as the methods described inJP-A-58-198483, International Patent Publication WO88/06155 and CanadianJournal of Chemistry (CAN. J. CHEM.), vol. 51. page 839 (1973).

The synthesis of an oxime (IV) from a ketone (IV) is carried out byreacting the ketone (IV) and an alkoxyamine (V) in water or in anorganic solvent (e.g., ethanol, methanol or acetic acid) in the presenceof an acid catalyst (e.g., hydrochloric acid) or a basic catalyst (e.g.,pyridine, aniline, sodium hydroxide or sodium carbonate) at atemperature between 0° C. and the reflux temperature of the solvent(water or organic solvent). In one preferred example, the reaction iscarried out in ethanol in the presence of pyridine at the refluxtemperature. In this reaction, the amount of the alkoxyamine (V) permole of the ketone (IV) is preferably 1.0 to 5.0 mol, particularlypreferably 1.0 to 2.0 mol.

Then the above-obtained oxime (VI) is converted to a Grignard reagent byreacting it with magnesium (Mg), and then carbon dioxide (CO₂) isreacted with the Grignard reagent to obtain a sulfide (IIa) (n=0 in theformula (II)) included in the aromatic carboxylic acid derivative of theformula (II). It is preferred to use ethers such as diethyl ether andtetrahydrofuran as a solvent. The reaction temperature is preferably-78° to 50° C., particularly preferably 0° to 50° C.

The molar amount of magnesium (Mg) used for obtaining the Grignardreagent is preferably 1.0 to 5.0 times as large as the molar amount ofthe oxime (VI). This reaction for forming the Grignard reagent ispreferably carried out in the co-presence of alkyl iodide such as methyliodide or alkyl bromide such as ethyl bromide, since this reactionproceeds smoothly. The molar amount of the alkyl halide used in thiscase is preferably 0.1 to 3.0 times as large as the molar amount of theoxime (VI).

The reaction between the Grignard reagent and carbon dioxide (CO₂) iscarried out by bubbling carbon dioxide gas from a bomb into the Grignardreagent in the solvent or by bubbling carbon dioxide gas generated fromdry ice (solid carbon dioxide) into the Grignard reagent in the solvent.Further, dry ice may be directly added to the Grignard reagent for thereaction. ##STR12##

An oxidizing agent (e.g., hydrogen peroxide, peracetic acid or sodiummetaperiodate) is allowed to react with the sulfide (IIa), obtained bythe above means (x), in a solvent (e.g., acetic acid, water or methanol)to obtain a sulfoxide (IIb) or a sulfone (IIc). When the oxidizing agentis allowed to react in an amount of 1 mole equivalent to the sulfide(IIa), the sulfoxide (IIb) is obtained. When the oxidizing agent isallowed to react in an amount of 2 mole equivalent to the sulfide (IIa),the sulfone (IIc) is obtained.

The process for the production of the novel pyrazole derivative of theformula (I), provided by the present invention, will be again explainedhereinafter. The novel pyrazole derivative can be obtained by thefollowing method (B) in addition to the method (A). ##STR13##

An oxidizing agent (e.g., hydrogen peroxide, peracetic acid or sodiummetaperiodate) is allowed to react with the sulfide of the formula (Ia)in a solvent (e.g., acetic acid, water or methanol) to obtain thesulfoxide of the formula (Ib) (n=1 in the formula (I)) included in thepyrazole derivative (I) of the present invention or the sulfone of theformula (Ic) (n=2 in the formula (I)) included in the pyrazolederivative (I) of the present invention. When the oxidizing agent isallowed to react in an amount of 1 mole equivalent to the sulfide (Ia),the sulfoxide (Ib) is obtained, and when it is allowed to react in anamount of 2 mole equivalent to the sulfide (Ia), the sulfone (Ic) isobtained.

The sulfide of the formula (Ia) used as a starting material in themethod (B) is included in the pyrazole derivative of the presentinvention, and it can be obtained by the following reaction. ##STR14##

Concerning the method of synthesizing the compound (Ia) by the reactionbetween the compound (IIa) and the compound (III), see the explanationgiven in the above method (A).

The present invention will be further explained hereinafter by referenceto Examples. However, the present invention shall not be limited bythese Examples.

(Preparation Examples of aromatic carboxylic acid derivative asintermediate compound)

Preparation Example 1

A reaction scheme is first shown for facile understanding of the subjectreaction. ##STR15##

(1) 3.0 Grams (12 mmol) of 5-methyl-6-bromothiochroman-4-one and 1.9 g(23 mmol) of O-methylhydroxylamine hydrochloride were refluxed underheat in a mixed solvent containing 10 ml of ethanol and 10 ml ofpyridine for 30 minutes. The solvents were distilled off under reducedpressure, and then 50 ml of 5% hydrochloric acid was added to form asolid. The solid was recovered by filtration, washed with water anddried to give 3.2 g of 4-methoxyimino-5-methyl-8-bromothiochroman (yield93%).

(2) 1.1 Grams (46 mmol) of magnesium was dispersed in 10 ml of THF, and2.2 g (20 mmol) of ethyl bromide was added dropwise under nitrogen. Theresultant mixture was allowed to react for 10 minutes, and then asolution of 2.9 g (10 mmol) of the4-methoxyimino-5-methyl-6-bromothiochroman obtained in the above (1) inTHF was gradually added at room temperature. The mixture was refluxedfor 3 hours and then cooled to room temperature, and carbon dioxide gaswas bubbled for 1 hour. 5% Hydrochloric acid was added to the reactionmixture, and the reaction mixture was extracted with ether. The etherlayer was extracted with 5% aqueous potassium carbonate, and the aqueouslayer was neutralized with concentrated hydrochloric acid. Theneutralized product was extracted with ethyl acetate, and the extractwas washed with saturated sodium chloride. The extract was dried oversodium sulfate, and the solvent was distilled off to give 1.8 g of4-methoxyimino-5-methylthiochroman-6-carboxylic acid (Compound a-1)(yield 63%).

Preparation Example 2

1.6 Grams of 4-methoxyimino-5,8-dimethylthiochroman-6-carboxylic acid(Compound a-2) was obtained from 5.4 g of5,8-dimethyl-6-bromothiochroman-4-one in the same manner as in Example 1(yield 30%).

Preparation Example 3

(1) 3.0 Grams (11 mmol) of 5,8-dimethyl-6-bromothiochroman-4-one and 2.2g (22 mmol) of O-ethylhydroxylamine hydrochloride were refluxed underheat in a mixed solvent containing 10 ml of ethanol and 10 ml ofpyridine for 30 minutes. The solvents were distilled off under reducedpressure, and then the residue was treated with 5% hydrochloric acid andextracted with ethyl acetate. The so-obtained solution was consecutivelywashed with 5% aqueous potassium carbonate and with saturated sodiumchloride solution and dried over sodium sulfate. The solvent wasdistilled off to give 3.2 g of4-ethoxyimino-5,8-dimethyl-6-bromothiochroman (yield 92%).

(2) 1.1 Grams (46 mmol) of magnesium was dispersed in 10 ml of THF, and2.2 g (20 mmol) of ethyl bromide was added dropwise under nitrogen. Theresultant mixture was allowed to react for 10 minutes, and then asolution of 3.2 g (10 mmol) of the4-ethoxyimino-5,8-dimethyl-6-bromothiochroman obtained in the above (1)in THF was gradually added at room temperature. The mixture was refluxedfor 3 hours and then cooled to room temperature, and carbon dioxide gaswas bubbled for 1 hour. 5% Hydrochloric acid was added to the reactionmixture, and the reaction mixture was extracted with ether. Theresultant ether layer was extracted with 5% aqueous potassium carbonate,and the aqueous layer was neutralized with concentrated hydrochloricacid. The neutralized product was extracted with ethyl acetate, and theextract was washed with saturated sodium chloride solution. The extractwas dried over sodium sulfate, and then the solvent was distilled off togive 1.6 g of 4-ethoxyimino-5,8-dimethylthiochroman-6-carboxylic acid(Compound a-3) (yield 57%).

Preparation Example 4

A reaction scheme is first shown for facile understanding of the subjectreaction. ##STR16##

1.0 Gram (3.8 mmol) of the4-methoxyimino-5,8-dimethylthiochroman-6-carboxylic acid (Compound a-2)obtained in the above Preparation Example 2 was allowed to react with1.3 g (12 mmol) of 30% hydrogen peroxide in 5 ml of acetic acid at 100°C. for 1 hour. Ethyl acetate was added to the reaction mixture, and thereaction mixture was washed with saturated sodium chloride solution anddried over sodium sulfate. The solvent was distilled off to give 1.1 gof 4-methoxyimino-5,8-dimethylthiochroman-6-carboxylic acid-1,1-dioxide(Compound a-4) (yield 97%).

Preparation Example 5

1.1 Grams of 4-ethoxyimino-5,8-dimethyl-thiochroman-6-carboxylicacid-1,1-dioxide (Compound a-5) was obtained from 1.0 g of4-ethoxyimino-5,8-dimethylthiochroman-6-carboxylic acid in the samemanner as in Preparation Example 4 (yield 98%).

Preparation Example 6

4-Isopropoxyimino-5,8-dimethylthiochroman-6-carboxylic acid (Compounda-6) was obtained from 5,8-dimethyl-6-bromothiochroman-4-one in the samemanner as in Preparation Example 1 with the yield being 34%.

Preparation Example 7

4-Isopropoxyimino-5,8-dimethylthiochroman-6-carboxylic acid-1,1-dioxide(Compound a-7) was obtained from4-isopropoxyimino-5,8-dimethylthiochroman-6-carboxylic acid (Compounda-6) in the same manner as in Preparation Example 4 with the yield being85%.

Preparation Example 8

4-Ethoxyimino-5-methylthiochroman-6-carboxylic acid-1,1-dioxide(Compound a-8) was obtained from 5-methyl-6-bromothiochroman-4-one inthe same manner as in Preparation Examples 3 and 4 with the yield being92%.

Table 1 shows the structures, amounts and yields of the compoundsobtained in Preparation Examples 1 to 8.

                                      TABLE 1                                     __________________________________________________________________________                         Synthe-                                                  Prep.                sized                                                    Ex.                  Compound               Amount                                                                             Yield                        No. Starting material                                                                              No.   Structural formula                                                                             (g)  (%)                          __________________________________________________________________________         ##STR17##       a-1                                                                                  ##STR18##       1.6  59                           2                                                                                  ##STR19##       a-2                                                                                  ##STR20##       1.6  30                           3                                                                                  ##STR21##       a-3                                                                                  ##STR22##       1.6  52                           4                                                                                  ##STR23##       a-4                                                                                  ##STR24##       1.1  97                           5                                                                                  ##STR25##       a-5                                                                                  ##STR26##       1.1  98                           6                                                                                  ##STR27##       a-6                                                                                  ##STR28##       1.3  34                           7                                                                                  ##STR29##       a-7                                                                                  ##STR30##       0.6  85                           8                                                                                  ##STR31##       a-8                                                                                  ##STR32##       1.2  92                           __________________________________________________________________________

Table 2 shows the physical properties of the compounds obtained inExamples 1 to 8.

                  TABLE 2                                                         ______________________________________                                        Pre-                                                                          paration                                                                             Com-                                                                   Example                                                                              pound   NMR (δ, ppm)                                             No.    No.     (deuterochloroform)                                                                             IR (cm.sup.-1)                               ______________________________________                                        1      a-1     2.73(3H, s), 2.8-3.3(4H, m)                                                                     --                                                          4.00(3H, s), 7.18(1H, s)                                                      7.72(1H, d)                                                    2      a-2     2.32(3H, s), 2.73(3H, s)                                                                        2970, 1700, 1270                                            2.7-3.3(4H, m)    1060                                                        3.99(3H, s), 7.75(1H, s)                                       3      a-3     1.32(3H, t), 2.33(3H, s)                                                                        2980, 2940, 1680                                            2.71(3H, s), 2.8-3.3(4H, m)                                                                     1280, 1260, 1050                                            4.25(2H, q), 7.75(1H, s)                                       4      a-4     2.65(3H, s), 2.73(3H, s)                                                                        3010, 2970, 1710                                            3.1-3.5(4H, m)    1320, 1130                                                  4.03(3H, s), 7.67(1H, s)                                       5      a-5     1.34(3M, t), 2.68(3H, s)                                                                        2990, 2950, 1680                                            2.74(3H, s), 3.1-3.7(4H, m)                                                                     1310, 1120                                                  4.28(2H, q), 7.76(1H, s)                                       6      a-6     1.29(6H, d), 2.32(3H, s)                                                                        3000, 1690, 1270                                            2.72(3H, s), 2.8-3.3(4H, m)                                                                     940                                                         4.41(1H, m), 7.74(1H, s)                                       7      a-7     1.31(6H, d), 2.63(3H, s)                                                                        2980, 1715, 1320                                            2.71(3H, s), 3.3-3.4(4H, m)                                                                     1140, 995                                                   4.46(1H, m), 7.65(1H, s)                                       8      a-8     1.35(3H, t), 2.72(3H, s)                                                                        3500-2900, 1720                                             3.2-3.5(4H, m), 4.30(2H, q)                                                                     1330, 1050                                                  7.89(2H, s)                                                    ______________________________________                                    

(Preparation Examples of pyrazole derivatives)

Preparation Example 9

A reaction scheme is first shown for facile understanding of the subjectreaction. ##STR33##

0.9 Gram (3.6 mmol) of the4-methoxyimino-5-methylthiochroman-6-carboxylic acid (Compound a-1)obtained in Preparation Example 1 and 0.44 g (3.9 mmol) of1-ethyl-5-hydroxypyrazole were dissolved in 5 ml of t-amyl alcohol, and0.81 g (3.9 mmol) of DCC (dicyclohexylcarbodiimide) was added at roomtemperature. The mixture was stirred at room temperature for 2 hours,and 0.74 g (5.4 mmol) of potassium carbonate was added. The mixture wasallowed to react at 90° C. for 8 hours. After the reaction, the solventwas distilled off, ethyl acetate was added, and the mixture wasextracted with a 5% aqueous potassium carbonate. The aqueous layer wasneutralized with concentrated hydrochloric acid, and then extracted withethyl acetate. The resultant extract was washed with saturated sodiumchloride solution, dried over sodium sulfate and concentrated to give0.88 g of4-methoxyimino-5-methyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman(Compound b-1) (yield 71%).

Preparation Example 10

4-Methoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman(Compound b-2) was obtained from the above Compound a-2 in the samemanner as in Example 9 with the yield being 67%.

Preparation Example 11

4-Methoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-3) was obtained from the above Compound a-4 in the samemanner as in Example 9 with the yield being 81%.

Preparation Example 12

4-Ethoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman(Compound b-4) was obtained from the above Compound a-3 in the samemanner as in Example 9 with the yield being 68%.

Preparation Example 13

4-Ethoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-5) was obtained from the above Compound a-5 in the samemanner as in Example 9 with the yield being 57%.

Preparation Example 14

A reaction scheme is first shown for facile understanding of the subjectreaction. ##STR34##

0.33 Gram (0.96 mmol) of the4-methoxyimino-5-methyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman(Compound b-1) was allowed to react with 0.3 g (2.7 mmol) of 30%hydrogen peroxide in 3 ml of acetic acid at 100° C. for 1 hour. Thereaction mixture was dissolved in ethyl acetate, washed with saturatedsodium chloride solution, and dried over sodium sulfate. The solvent wasdistilled off to give 0.35 g of4-methoxyimino-5-methyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1.1-dioxide(Compound b-6) (yield 97%).

Preparation Example 15

4-Methoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-3) was obtained from the above Compound b-2 in the samemanner as in Preparation Example: 14 with the yield being 97%.

Preparation Example 16

4-Ethoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-5) was obtained from the above Compound b-4 in the samemanner as in Preparation Example 14 with the yield being 98%.

Preparation Example 17

4-Isopropoxyimino-5,8-dimethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-7) was obtained from the above Compound a-7 in the samemanner as in Preparation Example, 9 with the yield being 52%.

Preparation Example 18

4-Methoxyimino-5.8-dimethyl-6-(1,3-dimethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-8) was obtained from the above Compound a-4 in the samemanner as in Example 9 except that the 1-ethyl-5-hydroxypyrazole inPreparation Example 9 was replaced with 1,3-dimethyl-5-hydroxypyrazole,with the yield being 70%.

Preparation Example 19

4-Methoxyimino-5,8-dimethyl-6-(1-methyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-9) was obtained from the above Compound a-4 in the samemanner as in Example 9 except that the 1-ethyl-5-hydroxypyrazole inPreparation Example 9 was replaced with 1-methyl-5-hydroxypyrazole, withthe yield being 68%.

Preparation Example 20

4-Ethoxyimino-5-methyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide(Compound b-10) was obtained from the above Compound a-8 in the samemanner as in Preparation Example 9 with the yield being 52%.

Tables 3 to 5 show the structures, amounts and yields of the compoundsobtained in Preparation Examples 9 to 20.

                                      TABLE 3                                     __________________________________________________________________________    Prep.    Synthesized                                                          Ex. Starting                                                                           Compound                  Amount                                                                             Yield                                 No. material                                                                           No.   Structural formula  (g)  (%)                                   __________________________________________________________________________     9  a-1  b-1                                                                                  ##STR35##          0.88 71                                    10  a-2  b-2                                                                                  ##STR36##          0.83 67                                    11  a-4  b-3                                                                                  ##STR37##          1.1  81                                    12  a-3  b-4                                                                                  ##STR38##          0.91 68                                    __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________    Prep.    Synthesized                                                          Ex. Starting                                                                           Compound                  Amount                                                                             Yield                                 No. material                                                                           No.   Structural formula  (g)  (%)                                   __________________________________________________________________________    13  a-5  b-5                                                                                  ##STR39##          0.74 57                                    14  b-1  b-6                                                                                  ##STR40##          0.35 97                                    15  b-2  b-3                                                                                  ##STR41##          0.35 97                                    16  b-4  b-5                                                                                  ##STR42##          0.35 98                                    __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Prep.    Synthesized                                                          Ex. Starting                                                                           Compound                   Amount                                                                             Yield                                No. material                                                                           No.   Structural formula   (g)  (%)                                  __________________________________________________________________________    17  a-7  b-7                                                                                  ##STR43##           0.56 52                                   18  a-4  b-8                                                                                  ##STR44##           0.72 70                                   19  a-4  b-9                                                                                  ##STR45##           0.71 68                                   20  a-8   b-10                                                                                ##STR46##           0.32 52                                   __________________________________________________________________________

Table 6 shows the physical property values of the compounds obtained inExamples 6 to 11.

                                      TABLE 6                                     __________________________________________________________________________    Prep. Compound                                                                Ex. No.                                                                             No.    NMR (δ, ppm)  IR (cm.sup.-1)                               __________________________________________________________________________    9     b-1    1.46(3H, t), 2.58(3H, s), 2.6-3.3(4H, m)                                                          --                                                        4.00(3H, s), 4.06(2H, q), 6.97(1H, s)                                         7.29(1H, s), 7.2-7.5(2H, m),                                                  (deuterochloroform)                                              10    b-2    1.45(3H, t), 2.32(3H, s), 2.53(3H, s)                                                             --                                                        2.8-3.3(4H, m), 3.98(3H, s), 4.07(2H, q)                                      7.19(1H, S), 7.42(1H, s), 8.17(1H, s)                                         (deuterochloroform)                                              11    b-3    1.47(3H, t), 2.50(3H, s), 2.74(3H, s)                                                             3010, 2970, 1740                                          3.36(4H, m), 4.04(3H, s), 4.08(2H, q)                                                             1640, 1140, 1060                                          6.03(1H, s), 7.28(1H, s), 7.34(1H, s)                                         (deuterochloroform)                                              12    b-4    1.31(3H, t), 1.47(3H, t), 2.32(3H, s)                                                             3150, 2980, 2940                                          2.51(3H, s), 2.8-3.3(4H, m), 4.06(2H, q)                                                          1740, 1620, 1240                                          4.22(2H, q), 6.04(1H, s), 7.18(1H, s)                                                             1220, 1050                                                7.35(1H, s) (deuterochloroform)                                  13    b-5    1.33(3H, t), 1.46(3H, t), 2.49(3H, s)                                                             3450, 3000, 1720                                          2.74(3H, s), 3.37(4H, m), 4.10(2H, q)                                                             1630, 1130, 1050                                          4.28(2H, q), 6.60(1H, s), 7.27(1H, s)                                         7.34 (1H, s) (deuterochloroform)                                 14    b-6    1.28(3H, t), 2.58(3H, s), 3.1-3.7(4H, m)                                                          3250, 2920, 1730                                          4.02(3H, s), 3.9-4.2(2H, m)                                                                       1630, 1130, 1050                                          7.5-8.0(2H, m), 7.82(1H, s) (d6-DMSO)                            17    b-7    1.31(3H, d), 1.46(3H, t), 2.48(3H, s)                                                             3450, 3000, 1660                                          2.74(3H, s), 3.2-3.5(4H, m)                                                                       1640, 1130, 990                                           4.08(2H, q), 7.25(1H, s), 7.34(1H, s)                                         (deuterochloroform)                                              18    b-8    1.67(3H, s), 2.40(3H, s), 2.70(3H, s)                                                             3450, 2950, 1740                                          3.2-3.7(4H, m), 3.59(3H, s)                                                                       1630, 1130, 1050                                          4.02(3H, s), 4.95(1H, s), 7.28(1H, s)                                         (d6-acetone)                                                     19    b-9    2.43(3H, s), 2.70(3H, s),                                                                         3430, 2940, 1710                                          3.2-3.7(4H, m), 3.67(3H, s)                                                                       1630, 1120, 1040                                          4.01(3H, s), 5.08(1H, s), 7.35(1H, s)                                         (d6-acetone)                                                     20     b-10  1.35(3H, t), 1.47(3H, t), 2.58(3H, s)                                                             3250, 3000, 1630                                          3.2-3.5(4H, m), 4.08(2H, q)                                                                       1120, 1050                                                4.30(2H, q), 7.31(1H, s), 7.74(2H, ABq)                                       (deuterochloroform)                                              __________________________________________________________________________

HERBICIDE EXAMPLE

(1) Preparation of Herbicide

97 Parts by weight of talc (trade name: Zeaklite) as a carrier, 1.5parts by weight of alkylarylsulfonic acid (trade name: Neoplex, suppliedby Kao-Atlas K.K.) as a surfactant and 1.5 parts by weight of a nonionicand anionic surfactant (trade name: Sorpol 800A, supplied by TohoChemical Co., Ltd.) were uniformly pulverized and mixed to obtain acarrier for a wettable powder.

90 Parts by weight of the above carrier and 10 parts by weight of onecompound taken from Compounds of the present invention obtained in theabove Preparation Examples (or 10 parts by weight of the followingcompound (a) or (b) as a comparative herbicide) were uniformlypulverized and mixed to obtain a herbicide.

The compounds (a) and (b) used as the comparative herbicides have thefollowing structures. ##STR47##

(2) Biological test (Foliar treatment test)

Seeds of weeds such as crabgrass, barnyardgrass, green foxtail,cocklebur, velvetleaf and slender amaranth and seeds of corn, wheat andbarley were sown in 1/5,000 are Wagner pots filled with upland soil, andcovered with upland soil. Then, the seeds were grown in a greenhouse,and when they grew to plants at one or two-leaved stage, a predeterminedamount of the herbicide prepared in the above (1) was suspended in waterand uniformly sprayed to foliar portions at a rate of 200 liter/10 are.Thereafter the plants were grown in the greenhouse, and 20 days afterthe treatment, the herbicide was determined for herbicidal efficacy andphytotoxicity to the crops. Table 7 shows the results.

The herbicidal efficacy and the phytotoxicity to the crops are shown onthe basis of the following ratings.

    ______________________________________                                                       Remaining plant weight/                                        (Ratings)      non-treated ratio [%]                                          ______________________________________                                        Herbicidal efficacy                                                           0               81-100                                                        1              61-80                                                          2              41-60                                                          3              21-40                                                          4               1-20                                                          5              0                                                              Phytotoxicity                                                                 -              100                                                            ±           95-99                                                          +              90-94                                                          ++             80-89                                                          +++             0-79                                                          ______________________________________                                    

The remaining plant weight/non-treated ratio was calculated by(remaining plant weight in treated area/remaining plant weight innon-treated area)×100.

                                      TABLE 7                                     __________________________________________________________________________                 Herbicidal efficacy                                              Test  Dosage       Barnyard-                                                                            Green       Velvet                                                                             Slender                                                                             Phytotoxicity                Compound                                                                            [g (a.i.) are]                                                                       Crabgrass                                                                           glass  foxtail                                                                            Cocklebur                                                                            leaf amaranth                                                                            Corn                                                                              Wheat                                                                              Barley              __________________________________________________________________________    (a)   12.5   0     0      0    0      0    1     --  --   --                  (b)   3.2    0     0      0    3      3    2     --  --   --                  b-1   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    4      5    4     --  --   --                  b-2   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-3   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-4   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-5   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-6   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-7   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-8   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-9   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                   b-10 12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  __________________________________________________________________________     a.i. = abbreviation for active ingredient                                

(3) Biological test (Soil treatment test)

Seeds of weeds such as crabgrass, barnyardgrass, green foxtail,cocklebur, velvetleaf and slender amaranth and seeds of corn, wheat andbarley were sown in 1/5,000 are Wagner pots filled with upland soil, andcovered with upland soil. Then, a predetermined amount of the herbicideprepared in the above (1) was suspended in water and uniformly sprayedonto the soil surface. Thereafter the seeds were grown in thegreenhouse, and 20 days after the treatment, the herbicide wasdetermined for herbicidal efficacy and phytotoxicity to the crops. Table8 shows the results.

                                      TABLE 8                                     __________________________________________________________________________                 Herbicidal efficacy                                              Test  Dosage       Barnyard-                                                                            Green       Velvet                                                                             Slender                                                                             Phytotoxicity                Compound                                                                            [g (a.i.) are]                                                                       Crabgrass                                                                           glass  foxtail                                                                            Cocklebur                                                                            leaf amaranth                                                                            Corn                                                                              Wheat                                                                              Barley              __________________________________________________________________________    (a)   12.5   1     1      0    0      1    1     --  --   --                  (b)   3.2    1     1      1    2      0    0     --  --   --                  b-3   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     4      5    4      5    5     --  --   --                  b-5   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-6   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-7   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-8   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  b-9   12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                   b-10 12.5   5     5      5    5      5    5     --  --   --                        3.2    5     5      5    5      5    5     --  --   --                  __________________________________________________________________________     a.i. = abbreviation for active ingredient                                

Tables 7 and 8 clearly show that the pyrazole derivative-containingherbicide of the present invention shows no phytotoxicity to corn, wheatand barley and exhibits an excellent weed control effect on grasses(crabgrgrass, barnyardgrass and green foxtail) and broad-leaved weeds(cocklebur, velvetleaf and slender amaranth) at a low dosage. Incontrast, the herbicide containing the known pyrazole derivative (a) andthe herbicide containing the known pyrazole derivative (b) do notperform any sufficient herbicidal efficacy.

As specified above, according to the present invention, there have beenprovided the novel pyrazole derivatives or salts thereof which show highselectivity to corn, wheat and barley and which are capable ofcontrolling grasses and broad-leaved weeds at a low dosage: a herbicidecontaining one of the above novel pyrazole derivatives and/or salesthereof as an active ingredient: and novel intermediate compoundssuitable for the production of the above novel pyrazole derivativesand/or salts thereof.

We claim:
 1. An aromatic carboxylic acid compound of the formula (II).##STR48## (wherein R¹ is a C₁ -C₆ alkyl group, each of X¹ and X² isindependently a C₁ -C₄ alkyl group, m is an integer of 0 or 1, and n isan integer of 0, 1 or 2, or a salt thereof.
 2. The aromatic carboxylicacid compound or a salt thereof according to claim 1, wherein R¹ is a C₁-C₄ alkyl group.
 3. The aromatic carboxylic acid compound or a saltthereof according to claim 2, wherein R¹ is methyl, ethyl or i-propyl.4. The aromatic carboxylic acid compound or a salt thereof according toclaim 1, wherein X¹ is methyl.
 5. The aromatic carboxylic acid compoundor a salt thereof according to claim 1, wherein X² is methyl.
 6. Thearomatic carboxylic acid compound or a salt thereof according to claim1, wherein m is
 0. 7. The aromatic carboxylic acid compound or a saltthereof according to claim 1, wherein X² is substituted on the8-position when m is
 1. 8. The aromatic carboxylic acid compound or asalt thereof according to claim 1, wherein n is 2.